What is the hazard level of neutron radiation?

• A. Internal hazard only
• B. External hazard; highly penetrating and long range
• C. No hazard
• D. Short-range hazard only for skin

Answer: (B)

Neutron radiation presents an external exposure hazard because neutrons are highly penetrating and travel long distances through matter. They are uncharged, so they don’t ionize like alpha or beta particles, but they transfer energy by colliding with nuclei, allowing them to pass through skin, clothing, and many shielding materials and still deliver dose far from the source. This makes shielding requirements relatively substantial and distance a key protection factor; the hazard isn’t limited to the immediate vicinity or to the skin surface.

While inhalation or ingestion could cause internal exposure, the dominant concern in typical field use is the external, long-range nature of neutron radiation. It’s not accurate to say there’s no hazard, and it’s not a short-range skin hazard, since neutrons penetrate deeply.